My son was diagnosed as bipolar at age 8. Less than a year ago he was foud wandering the streets in a psychotic state. He was admitted to the psyc unit. It was not true mania. He was on pcp and a butt load of other crap.
Youe son admitted to using "sleeping" medication. He has a history of abusing drugs. he has not been clean and functional long enough to say that drugs are not a possible cause. Only people on this forum would think that it would be great if it is "only" the mental illness causing the mania. I know I would have been thrilled. Before he can be reliably diagnosed with bipolar or any other severe mental illness, he will have to be completly drug free including "sleep" medication. Until then you will have to consider possible/probable drug use.
I hope he surfaces in one piece. I am glad that he did not take the money and that he does not have access to the car.